Containers made of flexible materials which hold and dispense liquids and granular material have been designed with spouts from which their contents are poured. Some of these containers are constructed by mounting an independent spout, more generally referred to as a fitment, to the body of the container as shown in U.S. Pat. No. 5,002,623. Such a fitment typically has a base from which a neck or spout extends. The neck may be provided with threads so that a cap may be threaded thereon to close the container.
Fitments have been designed to be heat welded to the outside surface of the body of the container about an opening. However, because of the flexibility of these containers these types of fitments are susceptible to separation from the body during container handling.
Fitments have also been designed to be mounted in an opening between two layers of plastic which form opposite sides of the container body. The opening is formed by sealing all but a portion of the side edges of the plastic layers as shown in U.S. Pat. No. 5,002,623. The fitment is mounted on a mandrel which is inserted into the opening. Once the fitment is inserted the remaining side edges of the plastic layers are sealed about the fitment base with the mandrel supporting the fitment against the pressure of the sealing plate. The sealing process may be done by heat welding, as shown in U.S. Pat. No. 4,023,607, or by any other commonly used welding processes.
Fitments for flexible containers have also been designed with bases that are larger in diameter than their necks so that the container bodies do not have to taper severely towards the fitment. This type of fitment aids in pouring by funneling the contents. However, because the fitment neck is narrower than its base a mandrel positioned through the neck cannot also fit flushly against the interior of the base during the sealing process since it could not thereafter be removed through the restricted neck. Therefore these fitments have been designed with thicker bases to endure the pressure of the sealing plate without deformation. Nevertheless, these thicker plastic fitments still tend to flex during sealing which oftentimes results in a defective seal. Additionally, the increased thickness of these fitments increases the quantity of plastic used in their construction thus increasing their weight and cost.
Fitments have also been designed with ridges along the exterior of their bases. During assembly the fitment is positioned upon a mandrel extending through the base which is flush with the interior of the fitment. The flexible material is positioned over the ridges during the welding process to aid in securing the fitment. However, these ridges increase the width of the fitment base as compared to the portions adjacent the ridges. This difference in material width causes an uneven transfer of heat to and through the fitment. The uneven heat transfer causes an uneven sealing of the fitment.
It thus is seen that a need remains for a method and apparatus for mounting a fitment of the type having a spout and base to flexible container body and to the resulting container. It is to the provision of such that the present invention is primarily directed.